1. Field of the Invention
The present invention relates to a computer graphics apparatus having an improved walk-through function in which a viewline (or, viewpoint) moves around on a computer graphics display and more particularly an improved function for calculating an expectation time for a calculation processing time and a display procession time of one frame of the computer graphics display.
2. Description of the Related Art
Recently, a computer graphics technique, which generates and processes predetermined patterns and images (these are called xe2x80x9cgraphicsxe2x80x9d) on a display is widely utilized in various fields, for example, buildings, video games, commercial films, education, etc. Particularly, the walk-through function is a basic function used for the above fields. For example, in the architectural field, it is desired that the viewpoint on the walk-through is close to an actual viewpoint because it is very important for a structural designer to check an outside view of the structure. Further, it is desirable to provide a computer graphics apparatus having simplified handling operations. Still further, it is very important to coincide the calculation processing time with the display processing time in order to obtain smooth animated images which are close to an actual motion.
The first object of the present invention is to provide an improved walk-through function in order to obtain a viewline which is close to an actual viewline in computer graphics by providing various walk-through attributes to the object.
The second object of the present invention is to provide an improved calculation of an expectation time in order to obtain smooth animated images in computer graphics.
In accordance with the present invention, there is provided a computer graphics apparatus including an input unit for receiving from a user a viewline moving instruction for moving the viewline on computer graphics; a viewline control unit operatively connected to the input unit for determining positions and directions of the viewline on the computer graphics; a storage unit operatively connected to the viewline control unit for storing computer graphics data at least including three-dimensional data of objects, walk-through attribute data and viewline data; an image generation unit operatively connected to the storage unit and the viewline control unit for generating images including animated images based on the position of the viewline and the computer graphics date; and an image display unit operatively connected to the image generation unit for displaying images generated by the image generation unit.
In a preferred embodiment, the viewline control unit comprises a downward object searching unit for searching for objects positioned under the viewline based on the walk-through attribute; a moving vector calculation unit for calculating a moving vector based on the walk-through attribute data and a viewline vector; and a viewline movement processing unit for moving the viewline along with the moving vector.
In another preferred embodiment, the viewline control unit further comprises a viewline height adjusting unit for adjusting the height of the viewline.
In still another preferred embodiment, the viewline control unit further comprises and interference processing unit for checking for a possibility of collision of the viewline with an obstacle when moving the viewline on the computer graphics.
In still another preferred embodiment, the obstacle is a wall as one kind of the walk-through attribute, and the viewline is moved along with the wall when the viewline hits the wall.
In still another preferred embodiment, the interference processing unit holds data which is sorted into two objects in accordance with the different kinds of walk-through attributes, one performing an interference check, and the other not performing the interference check, whereby the numbers of objects performing the interference check are reduced in accordance with the sorted data and the walk-through attributes.
In still another preferred embodiment, the viewline control unit further comprises viewline width adjusting unit for moving the viewline along with the obstacle by keeping a predetermined constant distance from the obstacle.
In still another preferred embodiment, a computer graphics apparatus further comprises a walk-through attribute editing unit operatively connected between the input means and the storage unit for setting the walk-through of the viewline.
In still another preferred embodiment, the image generation unit performs a calculation process for the three-dimensional data, a display process for displaying results of calculation, and expectation process for estimating calculation processing time and display processing time in an expectation processing time; and estimates processing time for one frame of an animated image by summing the expectation processing time, the calculation processing time and the display processing time.
In still another preferred embodiment, the image generation unit obtains the numbers of move-changing data and a method for changing data from the three-dimensional data; obtains an amount of data and kinds thereof from the three-dimensional data; obtains expectation parameters which are previously determined based on above numbers, method, amount and kinds; and calculates the calculation processing time and display processing time based on expectation parameters.
In still another preferred embodiment, the image generation unit estimates the processing time in accordance with change of data from a previous frame.
In still another preferred embodiment, the image generation unit obtains changed data from the previous frame regarding the numbers of move-changing data and a method for changing data from the three-dimensional data; obtains changed data from the previous frame regarding an amount of data and kinds thereof from the three-dimensional data; obtains expectation parameters which are previously determined; and calculates the calculation processing time and display processing time based on expectation parameters.
In still another preferred embodiment, the image generation unit estimates the processing time based on two kinds of data, one being data which changes with time, the other being data which does not change with time, and the processing time based on the latter being set to a reference time.
In still another preferred embodiment, the image generation unit determines the processing time for non-moving objects in a view-volume as the same time of the previous processing time, checks change of number of moving objects in the view-volume, and calculates the processing time in the view-volume.
In still another preferred embodiment, the image generation unit determines the processing time based on the data, which do not change with time, as a just previous actual time.
In still another preferred embodiment, the image generation unit divides a whole three-dimensional data space into a plurality of partial spaces, applies data necessary for expectation to each of the partial spaces, and estimates the processing time.
In still another preferred embodiment, the image eneration unit obtains a volume ratio of a volume of the whole three-dimensional data space and the view-volume, calculates data necessary for expectation based on the volume ratio within the view-volume, and estimates the processing time.
In still another preferred embodiment, the image generation unit obtains a difference between previous expected processing time and an actual processing time, and corrects the expected processing time.
In still another preferred embodiment, the image generation unit comprises an expectation unit and an expectation parameter measuring unit; for reading data for measuring expectation parameters; displaying reference data for display; obtaining the display processing time for the reference data; displaying parameter decision data; obtaining the display processing time for the parameter decision data; obtaining expectation parameters for display process; executing a problem for expectation parameters for calculation process; obtaining calculation processing time; and obtaining the expectation parameters for calculation process.